Sony Walkman WM 101 fix advise

Dear all,
I've found my and my brothers historical walkman WM101 ( the first with gum rechargeble battery) stored for many years in garage. They are in great cosmetic condition but none of the two are working with putting a new battery. No led , no motor activity at all...I guess something related with capacitors gone. Is there someone who could give me some usefull advise on how to proceed in attemp to repair and where to look as first? I saw in service manual there is a cap immediately after battery connector... thanks for any help Enrico

 

Very nice, indeed!

No corrosion on the battery contacts? So first check if there is voltage at the battery contacts, then follow until you reach that capacitor, and so on if needed. I assume you have a multimeter?
Did you use the original gumstick batteries? Maybe they have gone bad.

 

First open it and check the condition of the belt ... being stopped for a while you will be glued to the engine that will not be able to turn and will seem dead ... connect a pair of headphones .. turn up the volume to the maximum without any cassette you should hear the background rustle ...

 

Thanks to both of you. in particular Silver ...When I put the headphone tere is a little noise on the background at the time of jack insertion. Then when I press play there is a very little attempt to spin on both of them. So maybe you are right about there is belt avoiding motor start. I will open it later. I'll keep you posted on progress.

 

Ottimo ..

 

If you can hear something it is not completely dead
Like said check the belt, normally you will have to change it.
If you try to turn the two reels by hand, do they turn easily ?

 

thanks dksp! yes I've already ordered a new pair of belts. when I try to turn by hand the reels they turn easily bytheway. I really hope that I could fix them. They are a major souvenir of my golden age

 

I've removed the back panel and the belt doesn't look so bad. When I put the battery I mesured voktage across the board it's 1.5V as the battery. But when I press one button (play or ff rewind) it goes down to 0.5V...

 

Maybe some sticky grease in the gears. I had the problem with my WM-501 which looks quite similar.

 

Now it's really weird...I put the voltmeter across battery gnd and the 1.5v test point market close to the headphone jack and it looks like the impedance have unlocked something and now it start spinning motor and turning on the red light. Then it works for some seconds ...then I have to disconnect battery and put again the tester beetween the two points mentioned to restore functionality for a couple of sec. I really start to think about something capacitive...

 

It was a profitable night....both WM-101 are now working , motor spinning in play and FF/FW. Now awaiting for the new belts in order to test audio and full functionalities. It's impressive the quality of enginerization for such a small device 34Y old. The first device use to have an unstable power contact plus the melted belt. The second just removing the melted belt was restart working properly. They looks as brand new and ready to work for another 40Y Keep Rocking! I should retrive the original carbon boxes and accessories that I've still stored and then I will post pictures. Thanks for the help!

 

I just realize that I was talking about WM102 , my mistake about the title . Bytheway someone knows the differences beetween WM101 and WM102?

 

Cool, great news!

 

Perfect Enrico .. Now can you sell me one ??

 

Check the micro leaf switches.
I have fixed 2 WM101 and a few F101 and the leaf switches need to be cleaned. I used wet dry sand paper and contact cleaner and fixed them.

 

So, what's the easiest way to remove the Pinch Rollers? I have new ones . I have the cassette cover off. I see there are 2 Springs also connected to the Head Support Assembly. There isn't enough clearance to remove the Pinch Roller Assembly. I have the original SM. Just trying to work smarter, not harder. I can't believe there are no videos on this one. I just didn't want to tear down more than needed or loose anything. I thought it would be a 45 minute job at most.

Thanks, Yes I know it's a older post. Side A seems to have just a little W & F and Side-B (Auto Reverse) is fine. I seen that was the common problem on these after age and sitting.

 

You need to remove the head carriage in order to replace the pinch rollers, there's not enough clearance to do it otherwise.
For this you will need to remove one of the 2 hinges that hold it and also the spring that holds the carriage in closed position.

Then you can proceed in removing the cut washer and remove the roller assembly.
After you get the roller assembly out, you need to use a tool to push the pin out (it comes upwards).
Be careful if you bend the roller bracket to straighten it back, the roller needs to rotate without any resistance.

Pay attention to the fact some of the hubs in these walkmans shrink over time and a new roller will slip on it.
There is a new type of roller assembly that solves this problem: https://www.ebay.com/itm/125756456667

 

Val

Valentin, Thanks for writing on here! Yes, I already purchased the complete Pinch Roller with hub from that person. I tell you, this actually harder than I thought with thos 2 Carriage Springs to keep it closed! The SM does say to hook to the top first, then the 2 hinges. I'm just taking my time. Thanks again.

 

Ok, Quality belt installed, New Complete Pinch Rollers and assembly.

-Side A has flutter all the time.
-Sometimes plays Left channel louder than Right Channel, and depends on the Cassette.
-Side B no Problems at all.

-Tape Speed Side A = 3084 K Side B=3192. So, there is a big difference I tried getting it more accurate at the time but ran out of time.

-Side A is a little louder in playback vs Side B. (Reels) Side B seems more smoother.

I haven't checked Azimuth with the oscilloscope yet.

I'm thinking it's a lubrication problem? Maybe Capstan dry? I just hate to take apart this nice one as I have no spare parts or experience with this model. Very nice condition and original case.

Any Suggestions on my next Diagnosis step? (I really think the Azimuth is OK. Side B is so perfect. But I can put it on a scope with a 6.3kHz tape and check the Phase).

Thanks for reading.

 

This suggests tape curling occurs at the pinch roller, creating azimuth instability. It can be caused by an imperfect alignment either of the roller or of the capstan.
A mechanical gauge (like this one: https://www.willyhermannservices.com/whsu_011.htm) is helpful in diagnosing these issues, but it's not impossible to do it visually.
Simplest thing to check is if the rollers are parallel to the capstans and if the capstan itself sits in the middle of cassette shell hole (you can compare with side B).

Louder mechanically or the sound is louder on side A ?
Speed difference is caused by much higher load on the motor on side A, since the speed is lower here. The increased load is also the source of wow&flutter.
This can be caused by a lubrication issue, higher pressure on the FWD pinch roller, some gears not engaging smoothly.

In regard to lubrication, I recommend lubricating everything: the capstan bearings, the idler pulley, the small gears that drive the reels, clutch shaft and the motor itself (which is easy to diassemble on these).
As inconvenient as this may sound, it's best to do everything at once and know it's done. After this step, you know for sure lubrication isn't a problem. Besides, it should be done as preventive maintenance anyway.

As for the azimuth adjustment itself, first you need to have a perfectly stable azimuth (with no variation between cassettes) and only then do a check/adjustment at the end.